The present invention is generally directed to processes for the preparation of hydroxygallium phthalocyanine (HOGaPc) compounds and to imaging articles and imaging processes thereof. More specifically, the present invention is directed to processes for transforming hydroxygallium phthalocyanine a Type I polymorph into a Type V polymorph, to imaging articles containing the Type V polymorph, such as a photoreceptor, and to imaging processes and apparatus using the imaging articles.
Problems associated with prior art polymorph interconversions include: (1) scalability limitations of roll-milling processes that are manifested in the inability to manufacture and handle milling vessels at sizes, for example, of and above about 50 to about 100 gallons; and (2) production of Type V hydroxygallium phthalocyanine that possesses photosensitivity properties inferior to those of material transformed to the Type V polymorph by the roll-milling process. Other operational and logistical problems include: potential operator exposure to solvent vapors during bead separation and slurry transfer sequences of the conventional roll-milling process.
The aforementioned problems are unsatisfactory and are overcome in the present invention.
The processes and articles containing the product of the processes of the present invention are useful in many electrostatographic applications, for example, in xerographic printers and copiers, and especially in color xerographic systems.